1. Field of the Invention
This invention relates generally to automatic assembly systems, and more particularly is directed to an automatic assembly system or apparatus in which trays carrying parts arrayed thereon are transported to locations near a working station and the parts are automatically assembled at the working station by a robot which carries out a plurality of assembling operations thereon.
2. Description of the Prior Art
It has been proposed to use robots for automatically assembling the mechanical decks of audio and video tape recorders. In the existing automatic assembly operations, a number of robots are positioned along a production line for sequentially performing the necessary assembly operations. Thus, it is known to assemble the mechanical decks of audio and video tape recorders in a substantially automatic or unattended fashion.
However, when a product formed of many parts, as are the mechanical decks of audio and video tape recorders, is assembled in such automatic fashion, a number of robots are required for each production line. By reason of the foregoing, each production line is expensive and, therefore, existing automatic assembling procedures can not be applied economically to products in relatively small scale production.
Although the number of robots required for each production line can be minimized by increasing the number of parts to be assembled by each robot, the existing parts feeding arrangements, such as, ball feeders, magazines and the like by which parts are fed one-by-one to the robot are limited in respect to the types of parts that can be handled that way. In other words, some of the various types of parts to be assembled by a robot can not be fed thereto one at a time from a magazine or the like. On the other hand, if the parts to be assembled are arrayed and transported on trays conveyed along the production line, the resulting parts supplying system can have multi-purpose characteristics, that is, it can be used for supplying substantially all of the various types of parts that may be assembled automatically by a robot. However, the so-called stocking station for accommodating a number of such trays is expensive and occupies a relatively large space. Thus, it is difficult to provide a number of such stocking stations for trays respectively carrying the various types of parts to be assembled within the work area or reach of a single robot. Furthermore, supplying the trays to the respective stocking station presents a problem and it is difficult and costly to achieve the necessary alignment of the parts on the trays at the respective stocking station.